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Motorcycles » rec.motorcycles.tech » nighthawk 550 electrical problem
| nighthawk 550 electrical problem [message #466542] |
Wed, 05 October 2005 03:48 |
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krusty kritter Wrote:
> jlpridge wrote:
> -
> I am going to purchase a stator for this bike. I have
> reached this decision because of the test results from the Clymer
> manual. There are five leads coming from the stator, 3 yellow, one
> white and one black. The resistance tests for the three yellow leads
> test within specs. However the test of the resistance between the
> white
> and the black lead failed. The result in specs would be 4-6 ohms
> whereas
> mine measures 1 ohm. And of course it failed the open circuit test
> you
> had me do. Do you have any other advice before I replace this stator.
> I
> have found a company who rebuilds them for less than $100 including
> shipping with a 1 year warranty.-
>
> Well, $100 for a stator sounds like a good deal, if you really *need*
> the stator. Have you pulled off the alternator cover to see if the
> rotor is actually *turning* when the engine is running? It's possible
> that the rotor isn't turning, or that what you actually have is an
> excited field alternator with brushes.
>
> If you take off that alternator cover, you'll either see a cooling fan
> (like in the parts fiche at www.partsfish.com) or you'll see the
> rigging for brushes.
>
> An excited field alternator won't pass the charging voltage test or
> the
> open circuit test if it's not getting DC voltage from the battery,
> through the brushes, to the rotor.
>
> Another guy had a CB650 and he was having problems and he also
> mentioned black and white wires going to his alternator. Those were
> the
> wires from the voltage regulator to the brushes.
>
> I'm curious as to what the black and white wires you mention are for.
> The only other thing I can think of is that your ignition system is
> not
> just a transistor ignition but is actually Honda's so-called "CDI"
> ignition system.
>
> If that's what it has, the black and white wires could be coming from
> a
> winding in the stator that puts out 50 to 100 volts to provide high
> voltage to the CDI module.
>
> If your motorbike has a CDI ignition system, you wouldn't get 12 volts
> on the ignition coil positive terminals when you turn the ignition key
> on, you'd get 50 or 100 volts when the engine was running and less
> when
> you were cranking the engine with the starter.
Krusty,
Your caution is why I asked before making the decision on this
one. Yes my alternator has a fan and yes the bike does have a cdi box
under the seat. The clymer manual says there is not test for that box.
It is either good or bad. Mine is good because the bike fires properly
when the pickup is working correctly. The rotor does turn as I
suspected. The test of that black wire and white wire is straight out
of the clymer manual and it fails the resistance test clearly on a
cheap multimeter and an expensive one. What I am not sure of is what
the significance of the resistance between these two leads that makes
the stator bad.
Jeff
--
jlpridge
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| Re: nighthawk 550 electrical problem [message #466543 ] |
Wed, 05 October 2005 16:21 |
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jlpridge <jlpridge.1wetwi [at] news.motorbikebanter.com> wrote:
>
> krusty kritter Wrote:
>> jlpridge wrote:
>> -
>> I am going to purchase a stator for this bike. I have
>> reached this decision because of the test results from the Clymer
>> manual. There are five leads coming from the stator, 3 yellow, one
>> white and one black. The resistance tests for the three yellow leads
>> test within specs. However the test of the resistance between the
>> white
>> and the black lead failed. The result in specs would be 4-6 ohms
>> whereas
>> mine measures 1 ohm. And of course it failed the open circuit test
>> you
>> had me do. Do you have any other advice before I replace this stator.
>> I
>> have found a company who rebuilds them for less than $100 including
>> shipping with a 1 year warranty.-
>>
>> Well, $100 for a stator sounds like a good deal, if you really *need*
>> the stator. Have you pulled off the alternator cover to see if the
>> rotor is actually *turning* when the engine is running? It's possible
>> that the rotor isn't turning, or that what you actually have is an
>> excited field alternator with brushes.
>>
>> If you take off that alternator cover, you'll either see a cooling fan
>> (like in the parts fiche at www.partsfish.com) or you'll see the
>> rigging for brushes.
>>
>> An excited field alternator won't pass the charging voltage test or
>> the
>> open circuit test if it's not getting DC voltage from the battery,
>> through the brushes, to the rotor.
>>
>> Another guy had a CB650 and he was having problems and he also
>> mentioned black and white wires going to his alternator. Those were
>> the
>> wires from the voltage regulator to the brushes.
>>
>> I'm curious as to what the black and white wires you mention are for.
>> The only other thing I can think of is that your ignition system is
>> not
>> just a transistor ignition but is actually Honda's so-called "CDI"
>> ignition system.
>>
>> If that's what it has, the black and white wires could be coming from
>> a
>> winding in the stator that puts out 50 to 100 volts to provide high
>> voltage to the CDI module.
>>
>> If your motorbike has a CDI ignition system, you wouldn't get 12 volts
>> on the ignition coil positive terminals when you turn the ignition key
>> on, you'd get 50 or 100 volts when the engine was running and less
>> when
>> you were cranking the engine with the starter.
>
>
> Krusty,
>
> Your caution is why I asked before making the decision on this
> one. Yes my alternator has a fan and yes the bike does have a cdi box
> under the seat. The clymer manual says there is not test for that box.
> It is either good or bad. Mine is good because the bike fires properly
> when the pickup is working correctly. The rotor does turn as I
> suspected. The test of that black wire and white wire is straight out
> of the clymer manual and it fails the resistance test clearly on a
> cheap multimeter and an expensive one. What I am not sure of is what
> the significance of the resistance between these two leads that makes
> the stator bad.
If you check out
http://electrosport.com/electrosport_electrical_honda.html
you will see the 1983 Nighthawk CB550SC uses the same regulator as
the 80-82 CB900C, among a number of other Honda models.
Having owned an 81 CB900C, I know for a fact that it has an excited
field alternator, using a spinning field coil (rotor) with brushes and
a commutator.
But- the Honda parts fiche does not show any brushes or a commutator for
the field/rotor coil, it just shows a stator with a single connector,
which at first glance, would tend to indicate it's a permanent magnet
style alternator. However, there is another possibility- it could be an
excited field type using a stationary field coil and spinning magnetic
reluctors, similar to the system used on my '77 KZ650B1. I think this
is the case. The two-piece rotor is a clue.
Unfortunately the stator / field coil combination is not sourced by
Electrosport, so either new Honda OEM or a used unit from ebay or a
breakers yard will be the most likely sources.
--
Mark '01 SV650S '99 EX250-F13 '86 GL1200A '81 CM400T
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| Re: nighthawk 550 electrical problem [message #466544 ] |
Wed, 05 October 2005 16:32 |
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jlpridge wrote:
> Your caution is why I asked before making the decision on this
> one.
My concern is to help you avoid spending money needlessly on parts that
may
not need replacement. The charging system, consisting of alternator,
rectifier regulator, and battery is the system most often misunderstood
and all the parts very often get replaced one at a time until the
problem is found and the owner gets stuck with perfectly good extra
parts.
> Yes my alternator has a fan and yes the bike does have a cdi box
> under the seat. The clymer manual says there is not test for that box.
> It is either good or bad. Mine is good because the bike fires properly
> when the pickup is working correctly. The rotor does turn as I
> suspected.
Good. Now that we are clear on those points, the only other possible
reasons why the stator wouldn't put out the required open circuit
voltage are that the magnets on the rotor have lost their permanent
magnetism and the distinctly odd ball possibility that the stator or
rotor is the wrong one for the motorcycle. (1)
It's certain easy enough to find out if the permanent magnet rotor is
still magnetized, just hold a piece of iron next to it and it will grab
the iron and hold it.
Permanent magnets can lose their magnetism from being heated, being
struck hard blows with a hammer, or from being exposed to an
electromagnetic field.
> The test of that black wire and white wire is straight out
> of the clymer manual and it fails the resistance test clearly on a
> cheap multimeter and an expensive one. What I am not sure of is what
> the significance of the resistance between these two leads that makes
> the stator bad.
> > However the test of the resistance between the white
> > and the black lead failed. The result in specs would be 4-6 ohms
> > whereas mine measures 1 ohm.
The indication of low resistance is that some of the windings of the
stator's CDI charging coils are shorted out.
When you run the open circuit voltage test on the yellow wires, are the
black and white wires also disconnected? If the black and white wires
are disconnected and the engine runs, that indicates to me that the CDI
system will start the engine on battery voltage too.
The indication from the 1 volt you got from the open circuit test (if
you checked from yellow to yellow to yellow with the engine running at
around 5000 RPM) is that the stator battery charging coils are also
shorted out.
The decision to spend $100 on having your stator rewound, is, of course
entirely up to you, and I hope that my explanations have helped you
make the correct decision.
(1)We read about the strange case a few years ago where the owner of a
Suzuki GS750 had mismatched the rotor from one motorbike to the stator
from another motorbike and the number of magnetic poles was incorrect
so the required north and south magnetic poles were not aligned with
the stator poles at the correct time and there was no voltage output.
As I recall, that fellow had one 12-pole part and one 18-pole part, and
that's why the north poles and south poles were never aligned to
produce voltage in the stator. That one was a real headscratcher.
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